1. Field of the Invention
The present invention is related to the field of high voltage commutation distributors for use with internal combustion engines and more specifically to uniquely removable spark plug terminals.
2. Description of the Prior Art
Electrical commutators for internal combustion engines are commonly called distributors and normally include a base attached to the engine, a cap and a shaft. The shaft is gear driven by the engine to rotate in synchronization with the engine. The shaft is normally mounted in the base with a bearing or bushing to provide low frictional rotation about a central axis of said base. A rotor element is attached to the shaft inside a commutation cavity defined by the distributor base and cap. The distributor cap is formed to mount on the base and contains several electrical contacts that are insulated from each other and connected to individual spark plugs of the engine. The rotor element may contain one or more commutation electrodes to provide electrical connection between a common high voltage source electrode and individual ones of the spark plug contacts on the cap. The common high voltage electrode is connected to an ignition coil and provides several areas positioned for arc-gap conduction registration from the rotor conductor. Spark plug wires are normally connected to the distributor in one of several ways.
U.S. Pat. No. 2,243,269 discloses a distributor in which the spark plug wires are inserted into the sockets of the distributor housing and are screw clamped in place so that the tip of the threaded screw penetrates the insulation of the spark plug wire and makes electrical connection with the wire itself. The screw is threaded into an embedded electrode and thereby completes a circuit to the spark plug wires from the commutation cavity of the distributor.
U.S. Pat. No. 3,542,976 illustrates a spark plug wire connection assembly whereby a partially stripped spark plug wire is inserted into a hollow terminal which extends over the insulation of the wire and clamps onto the stripped wire portion. The portion of the terminal extending over the insulation of the spark plug wire is crimped thereto. The terminal is then mated with a plug end of a spark plug electrode. The wire, terminal and plug electrode are insertable through the top of the distributor into a metal casing which contains a detent and keyway to insure proper angular orientation of the electrode within the cavity.
U.S. Pat. No. 3,951,508 illustrates a spark plug terminal for an ignition distributor cap whereby an exposed terminal is interconnected with an internal electrode member which receives energy from the commutation rotor. The terminal and electrode are permanently attached to the distributor cap and the spark plug wire is attached to a conventional female socket which mates with the exposed terminal extending upward from the distributor cap.
U.S. Pat. No. 4,023,546 discloses a distributor containing electrically conductive female sockets formed in a distributor cap whereby said sockets are each lined with electrically conductive material connected to an embedded electrode which extends into the commutation cavity for receiving energy from the commutation rotor. Therefore, the spark plug wire connection utilizes a male plug which is formed to mate with the female socket on the distributor cap.
In each of the above prior art references, the distributor cap requires electrically conductive electrodes or socket liners to be inserted or embedded therein. Whether such parts are formed at the time the distributor cap is molded, or later inserted, requires additional labor or machine handling which adds to the cost of the parts.